I just saw that in a follow-up answer he softened his position a bit:

יצאת צדיק – האמנם?

What is the difference between the program and journalism? Should they not publish that Nochi Dankner is standing trial for stock manipulation? That Olmert received envelopes of cash? That Rabbi Berland is a fraud? The immediate motive of journalists and police officers is to get a salary, achievements, and status, and their additional value-based motive (which presumably also exists, at least for some of them) does not seem different from the motive of the TV program editor. I should note that I personally tried watching the program and it really does create an unpleasant feeling of catching a person in his corruption. So I do not watch, because it's a bit embarrassing, gives me no pleasure, and is not especially enlightening either, but I am definitely glad that many other people do watch.

The Rabbi wrote:
"Speech is permitted if it is beneficial, not if its intention is benefit."

I did not really understand this sentence.
I would be glad if the Rabbi could explain.

If Reuven is about to do business with Shimon, and I know for certain that Shimon is a problematic person, it is permitted to tell Reuven that. This is harmful speech for a constructive purpose. The question is whether the permission to tell him depends on my intending it as a commandment or not. In my opinion, it does not. What matters is the benefit itself (the result), not the intention.

The Rabbi wrote that the parameter is an actual commandment, not intention for the sake of a commandment. But commandments require intention, so there is no commandment. And regarding Jael, even someone who denies divine providence like you admits that back then, in her time, there was providence, and the Omnipresent has many ways to save His people from utter destruction.

I did not understand what I wrote regarding a commandment and intention. I wrote that the main thing is the result, not the commandment.
As for "the Omnipresent has many ways," that itself is my question in the column about Rabbi Druckman. Why does saving a life override the Sabbath? After all, the Holy One, blessed be He, can save even without our committing a transgression. So it is clear that even in their days one may not rely on a miracle. Even if at times the Holy One, blessed be He, did intervene, we are not supposed to build on that. To my mind, that is exactly what it means to assume that He does not intervene, except in sporadic cases.

The Torah said that one must desecrate the Sabbath in order to save a life. God can save, but He commanded us to save. I do not know what the case with Jael is, but if the Torah did not say to act that way, then even if the people of Israel would be destroyed that way, well then, it is good to die for our Torah.
As for the permission of harmful speech, does the Rabbi understand that it is permitted for a constructive purpose because there is benefit and the prohibition disappears (which exists only when it causes harm), or because there is a commandment to help and that commandment overrides a prohibition, but there is still a basis for the prohibition?

First, the Torah did not say it. The Sages derived it. From the flow of the Talmudic passage it is quite clear that they assumed this even before the derivations. Second, see the column on Rabbi Druckman, where I discussed this phenomenon more broadly.
As for your question at the end, I did not understand it. Clearly harmful speech involves harm along with the benefit, but when there is benefit there is no prohibition. Are you asking whether this is complete permission or merely override? There is no practical difference in this case (nor even in contexts like ritual impurity and life-threatening danger).

I am only asking whether "benefit" is a commandment or not.

I do not think so necessarily. Though there are broad umbrella commandments such as "Love your fellow as yourself," under which almost everything can be included.

How does benefit permit and remove the prohibition of harmful speech? (Naively, I thought this was a case of a positive commandment overriding a prohibition.)

It has nothing to do with a positive commandment overriding a prohibition. When there is benefit, it is not defined as harmful speech. Harmful speech is only when you speak in order to harm.

Even after the benefit from the program has already been obtained, is it still permitted to watch it by force of the categorical imperative? Or the second the benefit has already been obtained, there is no permission, just as with electricity on the Sabbath due to life-threatening danger: if a secular person got up and desecrated the Sabbath and the benefit has already been realized?
I think that is the core of my claim (aside from the other elements of harmful speech that are not needed for the sake of the benefit, regarding which perhaps there is room to hear that they are needed for the ratings, and according to the Rabbi's ruling perhaps the harm is balanced by the benefit).

I think so. The program is meant to be watched, and the viewing will enable additional programs. Besides that, the benefit produced increases with every viewer. There is no situation in which the benefit has already been fully obtained.
When there is a situation in which the benefit has already been obtained, then of course it is forbidden to desecrate the Sabbath. I have already answered that on the site. That is not the discussion here.